https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117894
Bug ID: 117894
Summary: Elaborated-type-specifier with class/struct
incorrectly accepts union type when using a dependent
name
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: luigighiron at gmail dot com
Target Milestone: ---
The following code is incorrectly accepted by GCC:
struct A{
union B{};
};
template<typename T>void foo(T){
struct T::B b;
}
int main(){
foo(A());
}
In an elaborated-type-specifier, if the class-key used is class/struct then the
class shall be a non-union class and if the class-key used is union then the
class shall be a union. However, specifically with a dependent name and when
using class/struct GCC does not seem to follow this. Clang, MSVC, and EDG all
seem to reject this code. GCC rejects this code if the declaration of b is
changed to not use the dependent name (replacing T with A), or if the choice of
union and struct is swapped (swapping union with the struct in struct T::B).
